B-37. Function Name: UNLSN

Purpose: Send an UNLISTEN command
Call address: $FFAE (hex) 65454 (decimal)
Communication registers: None
Preparatory routines: None
Error returns: See READST
Stack requirements: 8
Registers affected: A

Description: This routine commands all devices on the serial bus to stop receiving data from the Commodore 64 (i.e., UNLISTEN). Calling this routine results in an UNLISTEN command being transmitted on the serial bus. Only devices previously commanded to listen are affected. This routine is normally used after the Commodore 64 is finished sending data to external devices. Sending the UNLISTEN commands the listening devices to get off the serial bus so it can be used for other purposes.

How to Use:

1. Call this routine.

EXAMPLE:

   JSR UNLSN

B-38. Function Name: UNTLK

Purpose: Send an UNTALK command
Call address: $FFAB (hex) 65451 (decimal)
Communication registers: None
Preparatory routines: None
Error returns: See READST
Stack requirements: 8
Registers affected: A

Description: This routine transmits an UNTALK command on the serial bus. All devices previously set to TALK will stop sending data when this command is received.

How to Use:

1. Call this routine.

EXAMPLE:

   JSR UNTALK